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Python CPU Feature Detection

Project description


Prototype of replacement for `` for high-performance Python modules.
Detects CPU features such as:

* SIMD instruction support
* Number of cores (both virtual and physical)
* Cache sizes

It is fast, with an import+execution time of ~1 ms

It is written in C99. It supports Windows with MSVC and Linux with GCC/LLVM
compilers. MacOSX should also work with GCC/LLVM but has not been tested.

It is licensed under Creative Commons Zero, so it may be freely incorporated
as a submodule into your own projects.

It needs to be tested on a variety of machines.


The module generates a `dict` called `CPUFeature` on import which contains
useful information regarding optimization and compilation for the host.
For my Intel i7-7820X Skylake CPU, it generates the following info:

> python -c "import cpufeature; cpufeature.print_features()"
VendorId : GenuineIntel
num_virtual_cores : 16
num_physical_cores : 8
num_threads_per_core : 2
cache_line_size : 64
cache_L1_size : 32768
cache_L2_size : 1048576
cache_L3_size : 11534336
OS_x64 : True
OS_AVX : True
OS_AVX512 : False
MMX : True
x64 : True
ABM : True
BMI1 : True
BMI2 : True
ADX : True
MPX : True
SSE : True
SSE2 : True
SSE3 : True
SSSE3 : True
SSE4.1 : True
SSE4.2 : True
SSE4.a : False
AES : True
SHA : False
AVX : True
XOP : False
FMA3 : True
FMA4 : False
AVX2 : True
AVX512f : True
AVX512pf : False
AVX512er : False
AVX512cd : True
AVX512vl : True
AVX512bw : True
AVX512dq : True
AVX512ifma : False
AVX512vbmi : False

Notes on Fields

* If `num_threads_per_core > 1` likely Intel Hyperthreading (or equivalent
architecture) is present. The physical core count may be unreliable in
virtual environments.
* Cache sizes are in bytes.
* For AVX2, check `AVX2` and `OS_AVX2`.
* For AVX512, check `AVX512f` and `OS_AVX512`. Python support for AVX512
instructions is highly limited outside of compilation with ICC. MSVC does not
have AVX512 support until MSVC2017.


* Based on FeatureDetector by Alexander Yee (
* Ported to Python by Robert A. McLeod, who added detection of cores, and cache

Release Notes


* Added detection of processors, cores, and cache sizes
* Created Python wrapper around FeatureDetector
* Reduced FeatureDetector to C99 for better cross-platform compatibility

Project details

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